This invention generally relates to valves and more particularly to a valve construction which will automatically either open or close in response to a previously predetermined ambient temperature level. Valves of this type are in common use and generally include a body having a flow path defined therethrough in which a movable valve member such as a stem or stem portion is aligned to move relative to a valve seat. Obviously the direction in which these stem or stem portions move in relationship to the valve seat is depended on the operational manner of the valve desired for a particular purpose, that is, the valve can be designed to automatically either open or close.
A spring or other resilient means is utilized to urge the movable valve member to its second position; however, such action is normally counteracted by restraining means engaged with the member so as to normally block such movement. The restraining means include a link separable as by fusing upon reaching a predetermined temperature level or frangible as upon receipt of an external signal, thereby triggering a series of mechanical movements enabling the valve member to move to its second position.
Examples of such devices are shown in U.S. Pat. No. 3,916,930 issued Nov. 4, 1975 and assigned to the assignee of the present application and applicant's co-pending application Ser. No. 865,016 entitled THERMAL VALVE filed Dec. 27, 1977. Although such constructions are particularly suited for a wide variety of small and medium sized valve installations, it would be desirable to provide a valve of a modified and novel construction particularly suited for larger type valve installations, i.e. suitable for use in valves 3 to 4 inches in diameter or larger.
It is accordingly a primary object of the present invention to produce a thermally responsive valve in which the restraining means normally acting to prevent movement of the valve member to a second position is retained in position in a novel manner particularly suited for large valve constructions in which considerable force is exerted upon the movable valve member.
A further object of the present invention is the provision of a novel valve construction in which an urging force of relatively large magnitude may be blocked from moving a valve member to a second position by at least one movable member in turn restrained by spaced portions in turn interconnected by means of a separable link which will separate as upon reaching a predetermined ambient temperature level or other external signal.
These and other objects of the present invention are accomplished by providing a valve body having a valve member adapted to be moved from a first to a second position by the action of an urging force thereupon. The force is restrained by means of a restraining device in the form of a generally planar closed configuration frame in which a portion of said frame includes a separable link. The link serves to interconnect spaced frame portions which in turn contact at least one elongated pin and maintain such pin in lateral contact with the movable member in its intended path of travel so as to temporarily block its movement. When the link is broken, the spaced portions are free to outwardly deflect away from each other by the action of a pair of flexible rods connecting them to a base portion of the frame. The valve can be reset to its first position by means of a unique resetting mechanism including a hub threadably received on a threaded portion of the movable member and restrained from rotation therewith such that the hub will move longitudinally relative to the housing to compress the spring within the housing when the movable member is rotated as by an attached hand wheel.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.